This download has been made available for PC users if they "prefer a clean install or you want to install on a virtual machine." This does not affect Windows 10 preview users who have already downloaded the 9879 build via the automatic Windows Update earlier in November. This will be the last major build update for the Windows 10 preview in 2014, as Microsoft will take a bit of a break before resuming in early 2015.

Do you prefer to get Windows 10 via Windows Update or with an ISO file?